AB0236 PRESENCE OF ANTI-CITRULLINATED POLYPEPTIDE ANTIBODIES DECREASES BONE MINERAL DENSITY IN BODY OF PATIENT WITH RHEUMATOID ARTHRITIS: A RETROSPECTIVE COHORT STUDY
Authors: I. Yoshii, N. Sawada
Journal: Annals of the Rheumatic Diseases (2022)

Background Presence of anti-citrullinated polypeptide antibodies (ACPA) is one risk factor of bone erosion of the joint in patients with rheumatoid arthritis (RA). However, bone absorption in the whole body is still not clarified in a longitudinal study. Objectives The aim of this study is to clarify effects of ACPA on bone mineral density (BMD) decrease using dual-energy X-ray absorptiometry (DXA) in patient with RA using retrospective longitudinal cohort study. Methods Patient with RA who were measured BMD in lumbar spine (LS) and total hip (TH) using dual-energy X-ray absorptiometry (DXA) at first consultation (baseline) and were treated for more than five years, were recruited. Follow-up started at BMD measurement and continued until the development of the first fracture or censoring at death, loss to follow-up or end of the study. Every patients have been followed up with monitoring of SDAI and Health Assessment Questionnaire Disability Index (HAQ) at every another to three months. Sharp/van der Heijde Score (SHS) was measured at baseline and every another year thereafter. BMD were measured every six months. Relationship between BMD and candidate risk factors including ACPA positivity and serum titer level, and other variants for BMD loss were evaluated statistically using linear regression analysis. Evaluations were performed for the absolute value of BMD and Z-score at baseline, mean value of these during follow-up, and change from baseline. Change of Z-score during follow-up was also compared between groups what classified according to ACPA positivity (ACPA positive/negative group). Results A total of 222 patients were recruited including 17 male (7.7%) and 205 female (92.3%). The mean age of the patients was 69.2 years old. Mean disease duration at baseline and follow-up length after baseline were 6.4 and 63.3 months, respectively. Mean SDAI score, HAQ score and SHS at baseline were 22.2, 0.516, and 6.6, respectively. The mean ACPA level and positive rate were 202.1 and 77.5%, respectively. Higher ACPA titer level correlated significantly low BMD and Z-score in TH ( p &lt;0.05), whereas ACPA positivity significantly correlated with low Z-score in LS and TH during follow-up using univariate models ( p &lt;0.05). The ACPA positivity also correlated with decrease of Z-score in both LS and TH using univariate models ( p &lt;0.05), whereas no significant correlation demonstrated using multivariate model. Change of Z-score in the ACPA positive group was significantly lower than in the ACPA negative group despite no significant difference of disease activity between the two groups demonstrated ( p &lt;0.05) (Table 1). Table 1. Comparison of the two groups parameters ACPA-positive (n=172) ACPA-negative (n=50) p-value female (%) 91.3 96.5 0.10 at baseline age (year-old) 65.4 71.3 &lt;0.001 disease duration (months) 7.7 4.6 &lt;0.001 RF (IU/L) 138.3 (197.1) 21.5 (49.3) &lt;0.001 SDAI 26.3 (24.0) 21.0 (17.8) &lt;0.05 HAQ 0.496 (0.618) 0.553 (0.639) 0.48 SHS 8.4 (8.2) 3.5 (5.0) &lt;0.001 BMD in LS (g/cm2) 0.825 (0.167) 0.849 (0.156) 0.23 BMD in H (g/cm2) 0.700 (0.140) 0.710 (0.132) 0.75 Z-score in LS -0.246 (1.300) 0.123 (1.392) &lt;0.05 Z-score in TH -0.062 (1.034) 0.261 (1.020) &lt;0.05 at follow-up follow-up length (months) 64.8 65.4 0.65 SDAI 4.5 (3.1) 5.1 (4.4) 0.22 HAQ 0.495 (0.616) 0.516 (0.544) 0.32 SHS 8.1 (8.2) 3.4 (4.8) &lt;0.001 BMD in LS (g/cm2) 0.839 (0.171) 0.870 (0.165) 0.16 BMD in TH (g/cm2) 0.710 (0.118) 0.713 (0.115) 0.99 Z-score in LS -0.008 (1.361) 0.368 (1.426) &lt;0.05 Z-score in TH 0.129 (0.902) 0.396 (0.891) 0.11 anti-osteoporotic drug administered, ever (%) 73.4 69.8 0.72 GCS administered, ever (%) 35.8 32.9 0.68 The values are presented as mean (SD) unless indicated otherwise. Statistically significant within 0.05 are shown as bold styles. Conclusion Presence of ACPA potentially have an independent risk of BMD decrease. Its action affects regardless gender and age. Disclosure of Interests None declared